Manuka Honey for Healing Horse Wounds (AAEP 2011)

With the popularity of natural treatments on the rise, it’s no surprise that manuka honey—which is produced by bees—visiting the manuka bush found exclusively in New Zealand, has gained a good deal of attention. Vendors claim that it has antibacterial wound-healing properties in humans and in experimental animals.

But can it help wounds heal faster in horses than they would if left untreated? Researchers at the University of Sydney decided to find out, and they presented their findings at the 2011 American Association of Equine Practitioners convention held Nov. 18-22 in San Antonio, Texas.

Presenter Andrew Dart, BVSc, PhD, Dipl. ACVS, ECVS, director of the university’s Veterinary Science Research and Clinical Training Unit, described two controlled studies in which he and colleagues used manuka honey on horse wounds. One evaluated UMF (Unique Manuka Factor) 20 manuka honey to see if it helped heal wounds faster, while the second compared a 66% manuka honey and water gel to 100% manuka honey for wound healing.

“Honey has been used on wounds for many years, dating back to the ancient Egyptians, because its high sugar content and osmolarity draw water out of wounds and reduce edema (fluid swelling),” Dart said. “It also pulls water out of bacterial cells and helps kill them and has a low pH (slightly acidic).”

Manuka honey’s antibacterial activity works via the methylglyoxal compound, which affects bacterial RNA and protein synthesis, he explained. It has both antibacterial and immune-modulating properties, which he said makes it attractive as a wound-healing agent.

In the first study, the investigators contaminated wounds with feces for 24 hours in an attempt to recreate typical scenarios where limb wounds might be contaminated with dirt and/or feces for some time before being discovered by owners. Wound retraction (expansion of wound edges) and development of proud flesh (exuberant granulation tissue) are often observed with such wounds, noted Dart.

After 24 hours researchers treated half the wounds with manuka honey (the other have was left as an untreated control group). The wounds were bandaged and treated daily for 12 days. Dart reported that manuka honey-treated wounds were slightly smaller than control wounds at Day 5 and significantly smaller from Day 7 until Day 35. With application of manuka honey for 12 days there was no significant effect on the overall time to wound healing compared to untreated control wounds.

In the second study Dart and his colleagues evaluated the more user-friendly 66% manuka honey water-based gel, which could be used on the wounds without a bandage. Pure manuka honey is liquid at room temperature, explained Dart, so it doesn’t keep contact with the wound for long without a bandage.

“We hypothesized that the gel would be as effective as pure manuka honey and that a longer treatment time would shorten overall time to wound healing,” he said. “We also thought there would be a greater effect on contaminated wounds.”

In this study, researchers treated contaminated and uncontaminated wounds with pure manuka honey or the gel for 12 days, with the manuka honey gel until healed, with a plain gel for 12 days, or not at all.

Dart noted that there were variations in the wound healing patterns between contaminated and uncontaminated wounds, however treatment with manuka honey had no positive interaction with contaminated wounds.

“All three manuka honey treatments were very similar,” Dart recalled. “Manuka honey gel-treated wounds healed fastest at 47 days.” In comparison, pure manuka honey-treated wounds healed in 52 days, while plain gel and control wounds took 64 days to heal.

“As a gel, manuka honey can be used safely to promote healing of equine wounds without the need for a bandage, thereby reducing complications and costs associated with long-term bandaging,” he summarized.